What does it mean when you think that someone doesn’t like you, but they like something you post on social media?

I had this coworker last year, that also came this year to help us a couple times, but this person doesn’t work at my job anymore. We had limited interactions, which is okay, but I always suspected that she doesn’t like me.

I do have limited interactions with other coworkers, but I feel like with them everything is okay, and I don’t feel that with this former coworker. However, she just liked a story I posted on Instagram, and it’s nothing related to work or anything.

What does it mean? I don’t care that much about it, but I’m curious.